Climate change impacts bird migration phenology,causing changes in departure and arrival dates,leading to potential mismatches between migration and other key seasonal constraints.While the impacts of climate change o...Climate change impacts bird migration phenology,causing changes in departure and arrival dates,leading to potential mismatches between migration and other key seasonal constraints.While the impacts of climate change on arrival at breeding grounds have been relatively well documented,little is known about the impacts of climate change on post-breeding migration,especially at stopover sites.Here we use long-term(11 years)banding data(11,118 captures)from 7 species at Mai Po Marshes Nature Reserve in Hong Kong,a key stopover site for migratory birds along the East Asian–Australasian Flyway,to describe long-term changes in migration phenology and to compare observed changes to annual weather variation.We also examine changes in wing length over a longer time period(1985–2020)as wing length often correlates positively with migration distance.We found that observed changes in migratory phenology vary by species;three species had later estimated arrival(by 1.8 days per year),peak(by 2.6 days per year)or departure(by 2.5 days per year),one showed an earlier peak date(by 1.8days per year)and two showed longer duration of passage(2.7 days longer and 3.2 days longer per year).Three species exhibited no long-term change in migration phenology.For two of the four species with shifting phenology,temperature was an important predictor of changing peak date,departure dates and duration of passage.Wing length was shorter in three species and longer in two species,but these changes did not correlate with observed phenological changes.The complex changes observed here are indicative of the challenges concerning the detection of climate change in migratory stopover sites.Continued monitoring and a better understanding of the dynamics of all sites in the migratory pathway will aid conservation of these species under global change.展开更多
Background: The alteration and loss of habitats are two of the main threats that biodiversity conservation is cur?rently facing up to. The present study describes the effects of a perturbation and restoration in a ree...Background: The alteration and loss of habitats are two of the main threats that biodiversity conservation is cur?rently facing up to. The present study describes the effects of a perturbation and restoration in a reedbed habitat on a bird assemblage. We studied the bird community of a wetland of central Spain between 1995 and 2009, during which time an anthropic perturbation altered the original structure of the habitat;subsequently, as a result of restoration works, the habitat returned to its original state.Methods: We evaluated the effects on six population and physical parameters of the birds at three different phases of their life cycles(breeding, wintering and post?breeding migration seasons) before, during and after the habitat alteration. GLM was used to analyze the influence of three independent variables(year, perturbation phase and temperature).Results: The relative abundance and the species richness values decreased when habitat was altered, but then recovered as a result of the regeneration works. This pattern was the clearest amongst specialist species. Breeding success also declined during the perturbation phase and then increased;likewise, the sex ratio changed given that the proportion of male birds increased when habitat was altered. These results are discussed in relation to changes on availability of resources in altered habitats, to the adaptive mechanisms in the exploitation of ecological requirements and to the selection of optimum and sub?optimum habitats by generalist and specialist species.Conclusions: Ecosystem restoration can favour the recovery of population indexes of specialist passerines, although it depends on the efficiency of the type of restoration activity performed and on the complexity of the habitat.展开更多
基金Funding was provided by an RAE Improvement Grant to(TCB)from the Faculty of Science at The University of Hong Kong。
文摘Climate change impacts bird migration phenology,causing changes in departure and arrival dates,leading to potential mismatches between migration and other key seasonal constraints.While the impacts of climate change on arrival at breeding grounds have been relatively well documented,little is known about the impacts of climate change on post-breeding migration,especially at stopover sites.Here we use long-term(11 years)banding data(11,118 captures)from 7 species at Mai Po Marshes Nature Reserve in Hong Kong,a key stopover site for migratory birds along the East Asian–Australasian Flyway,to describe long-term changes in migration phenology and to compare observed changes to annual weather variation.We also examine changes in wing length over a longer time period(1985–2020)as wing length often correlates positively with migration distance.We found that observed changes in migratory phenology vary by species;three species had later estimated arrival(by 1.8 days per year),peak(by 2.6 days per year)or departure(by 2.5 days per year),one showed an earlier peak date(by 1.8days per year)and two showed longer duration of passage(2.7 days longer and 3.2 days longer per year).Three species exhibited no long-term change in migration phenology.For two of the four species with shifting phenology,temperature was an important predictor of changing peak date,departure dates and duration of passage.Wing length was shorter in three species and longer in two species,but these changes did not correlate with observed phenological changes.The complex changes observed here are indicative of the challenges concerning the detection of climate change in migratory stopover sites.Continued monitoring and a better understanding of the dynamics of all sites in the migratory pathway will aid conservation of these species under global change.
基金Part of the logistics of the ringing station were granted from the Madrid Regional Government(Parque Regional del Sureste)the municipality of San Martín de la Vega,Iberdrola,Volcam program of Caja Ahorros del Mediterraneo and SEO/BirdLife
文摘Background: The alteration and loss of habitats are two of the main threats that biodiversity conservation is cur?rently facing up to. The present study describes the effects of a perturbation and restoration in a reedbed habitat on a bird assemblage. We studied the bird community of a wetland of central Spain between 1995 and 2009, during which time an anthropic perturbation altered the original structure of the habitat;subsequently, as a result of restoration works, the habitat returned to its original state.Methods: We evaluated the effects on six population and physical parameters of the birds at three different phases of their life cycles(breeding, wintering and post?breeding migration seasons) before, during and after the habitat alteration. GLM was used to analyze the influence of three independent variables(year, perturbation phase and temperature).Results: The relative abundance and the species richness values decreased when habitat was altered, but then recovered as a result of the regeneration works. This pattern was the clearest amongst specialist species. Breeding success also declined during the perturbation phase and then increased;likewise, the sex ratio changed given that the proportion of male birds increased when habitat was altered. These results are discussed in relation to changes on availability of resources in altered habitats, to the adaptive mechanisms in the exploitation of ecological requirements and to the selection of optimum and sub?optimum habitats by generalist and specialist species.Conclusions: Ecosystem restoration can favour the recovery of population indexes of specialist passerines, although it depends on the efficiency of the type of restoration activity performed and on the complexity of the habitat.
